The present invention relates to a handle or grip for hand operated tools such as files or rasps and the like, provided at one end thereof with a converging tang insertable into a plug-in channel in the handle. This invention also relates to a modifications of the handle of this kind in which a tubular insert is removably introduced into a blind bore in the handle and the tang of the tool is introduced into a plug-in channel in the insert.
Handles of the above described kind are known, particularly in the form of a molded piece of plastic material which during its manufacture is provided with a hole which later on but before the mounting of the handle on the tool is drilled up to produce the plug-in channel matching the shape and size of the tang of a particular hand tool. Apart from the disadvantage that this additional drilling step complicates the manufacture and increases manufacturing costs, once the handle has been fitted by the manufacturer to a specific tool, it cannot be used for other tools having different configurations of their tangs. If a user of the handle needs a new handle the size and shape of the tang must be exactly specified and the handle finished by the manufacturer matches the corresponding tool only. If the specification of the tang dimensions is not available, the fit of the handle cannot be guaranteed. Another disadvantage of prior art handles is also the fact that once a fitting plug-in channel has been bored and the handle secured to the tool, it cannot be removed and attached to another tool having different size and shape of its tang. Moreover, in manufacturing preshaped handle pieces of plastic material there occur manufacturing problems inasmuch as in order to produce a hole of relatively small diameter, a correspondingly small core in the form is to be used which frequently has insufficient mass to permit the formation of cooling channels for the internal cooling. In the absence of cooling of the core there is always a risk during the shaping process that in the inner hollow spaces shrink holes or cavities and the like irregularities are created which later on may cause cracks or similar damages. It is also a disadvantage of prior art handles adjusted in advance to a particular tang of a tool, it cannot be guaranteed that after the insertion of the tang into the plug-in channel of the handle the tool is really permanently and ridgedly anchored in the handle.
In the prior art embodiment of a handle having a tubular insert in an axial blind bore, it is possible during the manufacture of preshaped handle pieces of plastic material to provide the cooling channels in the core for shaping the axial blind bore. However, even in this case the disadvantage remains that depending on the shape and size of respective two tangs a corresponding adjustment of the clearance of the axial bore on the handle piece is necessary so as to match the corresponding insert. It is true that the additional drilling step for the adjustment of the plug-in channel to the particular tang size is dispensed with, nevertheless the axial bore for receiving the insert must be designed such as to firmly hold inserts for different sizes of tangs. In practice, this requirement cannot be fulfilled for a broader range of tang sizes. Even if the inserts can be shaped to fit different sizes of the tangs, the spectrum of applicable tool shanks is limited and in addition the requisite firm seat of the insert in the receiving axial bore is questionable.